"At the end of the day, I've made some rookie mistakes," Manziel said Friday after the Cleveland Browns' veterans finished their conditioning test. "There were some things I wish I could have gone back and done a little differently."

Manziel's words came after several offseason photos showed him partying and enjoying life at various locations around the country. The Northeast Ohio Media Group, citing an anonymous source, reported Friday that the Browns were "alarmed" at a photo of the quarterback rolling a $20 bill in a Las Vegas bathroom.

Manziel and first-year coach Mike Pettine both declined to comment on the photo.

"I've talked about that with Coach Pettine, talked about it with [general manager] Ray Farmer and the people I need to talk about that with," Manziel said. "Moving forward they're good with everything and I've told them everything I need to and everything's been good."

Pettine said he had some "general" conversations with Manziel about the offseason, but when asked about the photo in particular, he said he wasn't going to "address individual incidents."

"I know we've had a long offseason of all these other things," Pettine said. "But now it's time for football."

While admitting mistakes, Manziel steadfastly defended his right to go out and enjoy himself in the offseason.

"I don't think there's anything wrong with me going out and having a nightlife and a social life," Manziel said. "I'm 21 years old, and it was the offseason and it's free time for us."

Manziel will start training camp as the backup. Pettine said that for the first two days, Brian Hoyer will get the snaps with the starters, and then the team will decide how best to proceed. Hoyer said he wants the best quarterback to play for the Browns and he believes he can be that guy.

"I think I feel the same way about it as I did when I left," Hoyer said. "It's my job, and until someone tells me otherwise, that's how I feel about it."

As for the constant attention to Manziel's photos with rolled bills and floating swans, Hoyer shrugged.

"I don't concern myself with that," he said. "I really focus on myself. What people do when they leave this building, that's up to them. We're all adults. It's none of my concern."

Hoyer and Manziel both spoke confidently, but the latter admitted there's much more on his plate than he's accustomed to -- longer play calls, pre-snap reads, a more complex playbook.

Manziel does not, however, believe anything that happened in the offseason hurt his chances to be the starter.

"I think there are definitely things I can do moving forward to help better act as a professional," Manziel said. "At the same time, I'm still learning how to do that, still getting used to this role, still getting used to this league, still getting used to being a professional football player. I'm not in college anymore. There's things I need to do better, and that's just part of being a professional. Hopefully with time and going through this season and as time goes on [I'll] get better at doing that."